In the operation of systems in a which a heat transfer fluid, refrigerant, jet, diesel or automotive fuel, liquid petroleum lubricant or similar fluid is either used or processed, high concentrations of suspended solid material and entrapped water therein can cause considerable difficulty by either clogging or otherwise obstructing the free passage of said fluids through process piping. Suspended solids such as dirt, metal chips, rust and other foreign material in the fluid can deposit in and clog piping, valves and other process equipment and, in time, necessitate that the operating system be shut down to remove one or more of these solids. In many applications, all particles down to about one micron in size must be removed if these problems are to be avoided.
Also, in many of these fluids, water tends to form hydrated sludges which are difficult, if not entirely impossible, to pump. Excessive quantities of entrapped water can result from such factors as:
(1) inadequate drying or improper storage of factory or refinery supplied fluids; PA0 (2) storage tank vent "breathing"; PA0 (3) inadequate total suction head in pumps; and/or, PA0 (4) process piping exposed to water during assembly, installation or repair operations.
Where free standing or absorbed water is a problem, many of these fluids are normally considered to be "wet" when the moisture content therein exceeds about 150 ppm at 70.degree. F. and, in many refrigeration systems, levels below 100 ppm must be maintained if problems such as sludge formation, acid and icing in the cooling coils are to be avoided.
Normally, an operating system using one or more of the these fluids in bulk will include at least one, if not more subsystems adapted to remove, on a more-or-less continuous basis, a sufficient amount of these types of solid and hydrous materials to prevent clogging, ice up and similar difficulties. The removal of suspended material usually involves passing contaminated fluid through one or more strainers and/or filters placed in the process line, while water removal, when necessary, is usually accomplished by passing the fluid through a desiccant such as Anhydrite or Drierite. However, to achieve and preserve the integrity of the cleaned/dried fluid and the system in which it is used, these operations must usually be performed continuously with in-line subsystems, with the result that problems with excessive pressure drop and, in the case of water removal, excessive heat generation may occur. Further, with such filtration systems, it is often necessary to shut down the operating unit of which the filtration subsystem is a part to remove, replace and/or repair it.